Triplet 2.8 to Sony NEX lens mount adapter

thingiverse

Sony NEX/E Mount Adapter for Soviet Triplet 2.8/78 Lenses. This adapter allows you to attach old Soviet projector lenses or similar-sized lenses to a Sony NEX/E-mount camera body. To focus on your desired objects, simply rotate the lens inside the adapter barrel and use the manual focus aid on your camera screen. A small 1.5 mm hole in the mount body provides a screw guide for the lens via a helical groove. This method is the easiest way to achieve precise lens alignment, as printing grooves directly into the mount can be inaccurate. Instead, one screw holds the entire assembly securely in place. If your Soviet Triplet lens has a diameter greater than 52.5 mm, you may need to adjust the internal barrel diameter for smooth rotational movement and proper fit. The ideal situation is when the lens sits snugly within the barrel but still allows for effortless rotation. The flange-to-flange distance of this adapter measures approximately 26mm (25.4 mm technically). This distance ensures infinity focus without any margin, although you may need to tweak the Z scale up or down by about 1% to achieve optimal results with your printer. This package includes three model files: PRT for tweaking barrel dimensions, and STP and STL for printing. The PRT file allows you to adjust the barrel dimensions while keeping the mount portion consistent. If downloaded as triplet_nex_26mm.1, rename it to triplet_nex_26mm.prt before opening in a CAD editor.